Patent attributes
An objective is to provide an avalanche photodiode that is excellent in device characteristics such as reliability. An avalanche photodiode is provided, which includes a substrate 1 formed with a light receiving region 3 on a multiplication layer 119, and formed with layers of differing semiconductor type with the multiplication layer 119 intervening, a ring-shaped groove 7 formed on the end face of the substrate 1 on its light-receiving-region side, in such a way that the groove surrounds the light receiving region 3, and one or more steps 5 provided on a side wall of the ring-shaped groove 7, in a range of from ¼ to ¾ of the depth of the groove. In the avalanche photodiode described above, because one or more steps provided on the side wall of the ring-shaped groove in the range of from ¼ to ¾ of the depth of the groove, discontinuity at the edge of the ring-shaped groove can be effectively prevented from occurring; consequently, an avalanche photodiode excellent in device characteristics such as reliability can be obtained.
